Exploring the multi-faceted potential: Synthesized ZnO nanostructure - Characterization, photocatalysis, and crucial biomedical applications.

This research describes the methodology for synthesizing zinc oxide nanoparticles (ZnO-NPs). It demonstrates a unique, cost-effective, and non-toxic chemical technique for producing ZnO-NPs using the precipitation method with NaOH as reducing and capping agents. The formed nanoparticles have been characterized and analyzed using numerous techniques such as; Fluorescence emission spectroscopy (FL), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray Spectroscopy (EDX), ultraviolet-visible optical absorption (UV-Vis), Fourier transform infrared spectroscopy (FTIR), and Thermal gravimetric analysis (TGA). Also, the analytical technique X-ray diffraction studies has been used which showed that the ZnO-NPs had a Wurtzite hexagonal crystal structure with an average crystallite size of 34.27 nm. The form and the size of the synthesized ZnO-NPs have been seen in SEM and TEM photographs. Using J-image, particle size has been obtained at 13.33 nm, and the grain boundaries were all approximately spherical. Peaks in the FT-IR spectrum of the NPs indicate the presence of carboxylate (COO) and hydroxyl (O-H) functional groups. According to these findings, Zn interstitial defects are responsible for the 380 nm emission peak. Since EDX could not identify any impurities below the detection threshold, we may be sure that Zn and O are the principal components of the synthesized sample. ZnO-NPs cause an absorption band at 350.34 nm in the UV-Vis spectrum and a band gap of 3.24 eV. The catalytic activity of the synthesized ZnO nanoparticles (NPs) was evaluated by investigating their effectiveness in degrading crystal violet (CV) and methylene blue (MB) dyes, along with assessing the degradation rates. The results demonstrated a high degradation efficiency, with ZnO NPs achieving approximately 96.72 % degradation for CV and 97.169 % for MB dyes, underscoring their remarkable efficacy in the degradation process. As for antimicrobial activity assessment, the results revealed that the ZnO-NPs had negligible impact on Gram-negative bacteria, whereas they exhibited a discernible effect on Gram-positive bacteria. Additionally, it showed anti-cancer potential against colon (SW480), breast (MDA-231), and cervix (HELA) lines cells as seen by (MTT) assay. Hence, due to its simplified processes and cheaper chemicals, our synthesis technique may use in industrial settings for various applications.

Thermal Behavior of Composite Material Based on Phase Change Material/Plaster as Thermal Energy Storage in Multilayer Wall: Experimental Study.

This study aims to explore the effects of augmenting the mass proportion of a composite comprising paraffin and beeswax (PBPCM) within plaster, which influences the thermal insulation of a dual wall. This work is primarily based on the thermal properties of the composite material PBPCM/plaster with varying percentages of PBPCM. Various essential parameters, such as density, thermal conductivity, specific heat capacity, thermal diffusivity, and latent heat, were assessed and juxtaposed with those of conventional plaster for the PBPCM/plaster composite material. The evaluation of this composite material was executed through an experimental device on a laboratory scale. The obtained results show that the increase in the mass fraction of PBPCM in the plaster decreased the thermal conductivity of plaster more than 3 times, whereas this increase of the PBPCM fraction in plaster enhances heat retention, specifically in specific heat capacity under constant conditions. Nevertheless, in a dynamic state, thermal effusivity has the lowest value for 50% PBPCM. The recommendation is to utilize 50% PBPCM, as it yields an optimal thermal effusivity, and significant values of specific heat capacity and latent heat have been noted for this percentage of PBPCM, measuring 1263.77 kJ/kg K and 18.9 kJ, respectively. Additionally, an increase in the PBPCM percentage narrows the temperature range suitable for effective thermal energy storage.

Experimental and Theoretical Studies of Hydrogen Storage in LaNi4.4Al0.3Fe0.3 Hydride Bed.

In this article, the experimental measurements of the absorption/desorption P-C-T isotherms of hydrogen in the LaNi4.4Fe0.3Al0.3 alloy at different temperatures and constant hydrogen pressure have been studied using a numerical model. The mathematics equations of this model contain parameters, such as the two terms, nα and nß, representing the numbers of hydrogen atoms per site; Nmα and Nmß are the receptor sites' densities, and the energetic parameters are Pα and Pß. All these parameters are derived by numerically adjusting the experimental data. The profiles of these parameters during the absorption/desorption process are studied as a function of temperature. Thereafter, we examined the evolution of the internal energy versus temperature, which typically ranges between 138 and 181 kJmol-1 for the absorption process and between 140 and 179 kJmol-1 for the desorption process. The evolution of thermodynamic functions with pressure, for example, entropy, Gibbs free energy (G), and internal energy, are determined from the experimental data of the hydrogen absorption and desorption isotherms of the LaNi4.4Al0.3Fe0.3 alloy.

Bi and Sn Doping Improved the Structural, Optical and Photovoltaic Properties of MAPbI3-Based Perovskite Solar Cells.

One of the most amazing photovoltaic technologies for the future is the organic-inorganic lead halide perovskite solar cell, which exhibits excellent power conversion efficiency (PCE) and can be produced using a straightforward solution technique. Toxic lead in perovskite can be replaced by non-toxic alkaline earth metal cations because they keep the charge balance in the material and some of them match the Goldschmidt rule's tolerance factor. Therefore, thin films of MAPbI3, 1% Bi and 0%, 0.5%, 1% and 1.5% Sn co-doped MAPbI3 were deposited on FTO-glass substrates by sol-gel spin-coating technique. XRD confirmed the co-doping of Bi-Sn in MAPbI3. The 1% Bi and 1% Sn co-doped film had a large grain size. The optical properties were calculated by UV-Vis spectroscopy. The 1% Bi and 1% Sn co-doped film had small Eg, which make it a good material for perovskite solar cells. These films were made into perovskite solar cells. The pure MAPbI3 film-based solar cell had a current density (Jsc) of 9.71 MA-cm-2, its open-circuit voltage (Voc) was 1.18 V, its fill factor (FF) was 0.609 and its efficiency (η) was 6.98%. All of these parameters were improved by the co-doping of Bi-Sn. The cell made from a co-doped MAPbI3 film with 1% Bi and 1% Sn had a high efficiency (10.03%).

The Effect of 600 keV Ag Ion Irradiation on the Structural, Optical, and Photovoltaic Properties of MAPbBr3 Films for Perovksite Solar Cell Applications.

A competitive new technology, organic metallic halide perovskite solar cells feature a wide working area, low manufacturing costs, a long lifespan, and a significant amount of large efficacy of power conversion (PCE). The spin-coating technique was utilized for the fabrication of pure CH3NH3PbBr3 (MAPbBr3) thin films, and these films are implanted with 600 keV silver (Ag) ions at fluency rate of 6 × 1014 and 4 × 1014 ions/cm2. XRD analysis confirmed the cubic structure of MAPbBr3. A high grain size was observed at the fluency rate of 4 × 1014 ions/cm2. The UV-Vis spectroscopic technique was used to calculate the optical properties such as the bandgap energy (Eg), refractive index (n), extinction coefficients (k), and dielectric constant. A direct Eg of 2.44 eV was measured for the pristine film sample, whereas 2.32 and 2.36 eV were measured for Ag ion-implanted films with a 4 × 1014 and 6 × 1014 ions/cm2 fluence rate, respectively. The solar cells of these films were fabricated. The Jsc was 6.69 mA/cm2, FF was 0.80, Voc was 1.1 V, and the efficiency was 5.87% for the pristine MAPbBr3-based cell. All of these parameters were improved by Ag ion implantation. The maximum values were observed at a fluency rate of 4 × 1014 ions/cm2, where the Voc was 1.13 V, FF was 0.75, Jsc was 8.18 mA/cm2, and the efficiency was 7.01%.

Photovoltaic Properties of ZnO Films Co-Doped with Mn and La to Enhance Solar Cell Efficiency.

In the present investigation, ZnO films co-doped with Mn and La were synthesized by the sol-gel technique. XRD analysis revealed that ZnO had a hexagonal structure. Mixed hexagonal and cubic phases appeared in ZnO containing Mn (1%) and La (1.5%). The grain size, d-spacing, unit cell, lattice parameters, atomic packing fraction, volume, strain, crystallinity, and bond length of co-doped ZnO films were determined as a function of doped ion contents. Through UV analysis, it was found that pristine ZnO had Eg = 3.5 eV, and it decreased when increasing the doping concentration, reaching the minimum value for the sample with 1% Mn and 1% La. The optical parameters of the films, such as absorption, transmittance, dielectric constants, and refractive index, were also analyzed. DSSCs were fabricated using the prepared ZnO films. For pure ZnO film, the values were: efficiency = 0.69%, current density = 2.5 mAcm-2, and open-circuit voltage = 0.56 V. When ZnO was co-doped with Mn and La, the efficiency increased significantly. DSSCs with a ZnO photoanode co-doped with 1% Mn and 1% La exhibited maximum values of Jsc = 4.28 mAcm-2, Voc = 0.6 V, and efficiency = 1.89%, which is 174% better than pristine ZnO-based DSSCs. This material is good for the electrode of perovskite solar cells.

Conception and Theoretical Study of a New Copolymer Based on MEH-PPV and P3HT: Enhancement of the Optoelectronic Properties for Organic Photovoltaic Cells.

A new copolymer has been studied, which is formed by Poly(2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene-vinylene) (MEH-PPV) and poly(3-hexylthiophene) (P3HT). The choice of these π-conjugated polymers was based on their semiconductor characters and their great applicability in electronic organic devices. The structure and vibrational and optoelectronic properties were simulated by calculations based on DFT, TD-DFT, and ZINDO. This material shows original and unique properties compared to the basic homopolymers. Thus, the obtained results reveal that this copolymer can be mixed with the (6,6)-phenyl C61 butyric acid methyl ester (PCBM) to give existence to a new composite that can be used as an active layer for an organic solar cell.

Green Synthesis of Silver Nanoparticles (Ag-NPs) Using Debregeasia Salicifolia for Biological Applications.

The synthesis of nanoparticles (NPs) using the green route is environmentally harmonious and cost-effective compared to conventional chemical and physical methods. In this study, the green synthesis of silver NPs was carried out using an extract of Debregeasia salicifolia. The synthesized Ag NPs were characterized by means of different techniques i.e., UV-Vis spectroscopy, FTIR spectroscopy, SEM, and XRD. The XRD pattern exhibited distinctive Bragg's peaks at (200), (111), (311), and (220). The XRD analysis confirmed the face-centered cubic geometry of the synthesized NPs and revealed that the nature of these NPs is crystalline. The synthesized NPs were verified for their antibacterial activities against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria. It showed that antibacterial activity of synthesized silver (NPs) was increased with increasing concentrations of both calcined and non-calcined NPs. The antioxidant activities of Ag NPs were also determined against ABTS at different concentrations for both calcined and non-calcined Ag NPs. Non-calcined Ag NPs have greater antioxidant activity than calcined Ag NPs. This report has a significant medicinal application, and it might open up new horizons in this field.

Absorption and desorption of hydrogen in Ti1.02Cr1.1Mn0.3Fe0.6RE0.03: experiments, characterization and analytical interpretation using statistical physics treatment.

In this work, the absorption and desorption isotherms of hydrogen on Ti1.02Cr1.1Mn0.3Fe0.6RE0.03 (RE = La, Ce, Ho) metals were collected at three temperatures under the same experimental conditions. This was carried out in order to determine the rare earth effect on the hydrogen storage performance of the Ti1.02Cr1.1Mn0.3Fe0.6 metal. The equilibrium data showing the hydrogen absorbed/released amounts per unit of absorbent mass have provided useful details to describe the absorption/desorption processes. Indeed, statistical physics formalism is appealing to ascribe advanced interpretations to the complexation mechanism. The physico-chemical parameters included in the model analytical expression are numerically determined from the experimental data fitting. We have found that the model can describe the complexation process through steric parameters such as the site densities (N 1m and N 2m), the numbers of atoms per site (n 1 and n 2) and energetic parameters (P 1 and P 2). The behavior of each parameter is examined in relation to the sorption mechanism. Overall, the energetic interpretation reveals that the desorption and absorption of H-gas in the Ti1.02Cr1.1Mn0.3Fe0.6RE0.03 alloys can be characterized by chemical interactions. In addition, the expression of the appropriate model is exploited to determine the thermodynamic potential functions that describe the absorption phenomenon.